Antirust agent



Patented Dec. 6, 1949 ANTIRUST AGENT Hastings S. Trigg and Henry D. Norris, Woodbury, and Ralph V. White, Pitman, N. J., assignors to Socony-Vacuum Oil Company, Incorporated, a corporation of New York No Drawing. Application February 8, 1947, Serial No. 727,304

7 Claims.

This invention relates to certain new compositions of matter formed by the interaction of alkenyl succinic acid anhydrides and' primary amines, and to lubricating oil compositions including these new reaction. products.

Various alkenyl succinic acids and their an- H hydrides, and many primary amines are known,

and some of these have been added to lubricating oils for various purposes. Insofar as is known, however, no reaction products of alkenyl succinic acid anhydrides with primary amines have been prepared, nor have any such reaction products been added to lubricating oils for an purpose. According to the present invention, it has been discovered that alkenyl succinic acid anhydrides may be reacted with primary amines to Produce reaction products of anentirely new type. It has further been discovered that certain of these reaction products when added to lubricating oil, effectively inhibit the formation of rust, even in the presence of sea water. The efiectiveness of these new reaction products in inhibiting rust formation is in distinct contrast to the properties of the reactants from which the products are made, which exhibit little or no tendency to inhibit rust formation under the same conditions. It has further been discovered that the new reaction products, when added in minor amounts to lubricating oil, not only inhibit rust formation on metals immersed therein or coated thereby but have no deleterious efl'ect on the lubricating oil in other respects, and probably improve the lubricating' oil in other characteristics as well as its rust inhibiting characteristics.

REACTANTS The new reaction products may be prepared from any alkenyl succinic acid anhydride, or any mixture thereof, and with any primar amine or mixture of primary amines. Either the anhydride or the amine may be used in a chemically pure or commercial state, and either may be a single compound or a mixture of a number of compounds. The amine may be an alkyl, aryl, cycloalkyl or heterocyclic amine, or may contain any combination of organic radicals. -Normal primary alkyl amines are preferred.

Alkenyl succinic acids may, less desirably, be used in place of their anhydrides, although this necessitates much more careful removal of water and often produces considerable amounts of undesirable by-products.

The preferred proportions in which the reactants are reacted is two molecular weights of the alkenyl succinic acid anhydride to one molecular weight or the primary amine. Products having as little as 1.25 molecular proportions of 2 alkenyl succinic acid anhydride to 1 molecular proportion of primary amine have been found efiective in inhibitingrust when incorporated in lubricating oil, and products having more than 2 molecular proportions of alkenyl succinic acid anhydride to 1 molecular proportion of primary amine are also effective for this purpose, although it does not appear that 1 molecule of primary amine can react with more than 2 molecules of alkenyl succinic acid anhydride and the effect of using more than 2 molecular proportions of alkenyl succinic acid anhydride is, therefore, apparently merely to dilute the final product with the excess of alkenyl succinic acid anhydride.

Products effective as rust inhibitors in lubricating oil can be prepared from primary amines having as few as 4 carbon atoms in the alkyl chain, provided the alkenyl succinic acid anhydride contains about 10 to 12 carbon atomsor more in the alkenyl radical. On the other hand, reaction products effective as rust inhibitors in lubricating oil can be prepared from alkenyl succinic acid anhydrides containing as few as 6 to 8 carbon atoms in the alkenyl radical if the primary amine contains around .12 carbon atoms in the alkyl chain. From this it appears that the total number of carbon atoms contained in the reactants is a critical factor when the reaction product is to be used as a rust inhibitor in lubricating oil. The indications are that the total number of carbon atoms in 2 mols of the anhydride and 1 mol of the amine should be no less than about 28 and preferably no less than 32 to give a product that will substantially inhibit rust when incorporated in lubricating oil in normal concentrations. On the other hand, the maximum totaal number of carbonatoms should not be more than about 50.. Accordingly, the sum of twice the number of carbon atoms per molecule of the alkenyl succinic acid anhydride and'of the I number of carbon atoms per molecule of the primary amine should be between 28 and 50.

A smaller total number of carbon atoms will give products which have some anti-rust activity, if the products are used in higher concentrations. The preferred reactants for producing rust inhibiting agents for use in oil are alkenyl succinic acid anhydrides containing about 10 to 12 carbon atoms in each alkenyl chain and primary amines containing about 10 to 14 carbon atoms per molecule.

REACTION CONDITIONS The reaction of the anhydride with the primary amine is quite easy of accomplishment and may be carried out in any number of ways, either in an open beaker or in a closed flask. A temperature of 75 C. is apparently necessary to cause the reaction to take place and temperatures in excess of about 140 C. are apparently undesirable in that they may cause undesirable side reactions or deterioration of the reactants or the reaction product. It is definitely preferable to use a temperature of between about 105 C. and about 115 C.

The time of reaction does not appear to be especially critical, the neutralization number of the final product indicating that the reaction is substantially complete in around 3 hours at the preferred temperature. Time and temperature In the examples. commercial alkenyl succinic acid anhydrides have been used. Instead of being a single, pure, chemical compound, these commercial anyhdrides are mixtures of alkenyl succinic acid anhydrides in which the alkenyl side chains range generally between certain limits.

are, however, interdependent, and a longer period of time is required at lower temperatures.

LUBRICATING 01L BASE The reaction products of this invention which are adapted for use as rust inhibitors in lubricating oils may be used in any type of lubricating oil ranging from gasoline and kerosene to petrolatum or petroleum wax. They may also be used .in synthetic lubricating oils or even in lubricatin oils or other lubricants derived from animal or vegetable sources.

The reaction products of this invention are particularly adapted for use in steam turbine oils, but are also effective in cutting oils, slushing oils, coating compositions, and compounded greases.

The products of this invention also inhibit rust when applied in other vehicles than oil, for example, benzene, toluene, xylol, petroleum ether or alcohol.

CONCENTRATION 1N OILS The preferred types of the new reaction products, that is, those containing at least about 32 carbon atoms for 2 molecules of the acid anhydride and 1 molecule of the primary amine, are effective in lubricating oils in concentrations ranging from about 0.003% to about 2.0%. It is preferred to use them in concentrations of from about 0.01% to about 0.10%. As is to be expected, a somewhat higher percentage is necessary to inhibit corrosion by sea water than is necessary to inhibit corrosion by fresh water, i. e., about 0.03% or more.

It is within the concept of this invention to improve lubricating oils in other respects than 0 their rust inhibiting characteristics by the addition of these same reaction products. Thus, the

pour point of the. oil, the viscosity index, and perhaps other characteristics may be improved by the addition of the new reaction products to oil in concentrations ranging as high as It is also within the concept of this invention to incorporate the new reaction products in oils containing other improving agents such as pour depressants, detergents, extreme pressure lubrication improvers, viscosity index improvers, antioxidants, stabilizing agents and the like.

It is further contemplated that the reaction products of this invention may be prepared and marketed in their pure form. that is, without ad mixture with lubricating oil, or may be prepared and marketed in concentrated solutions in oil, which concentrated solutions are adapted to be added to further quantities of oil to improve its characteristics.

They are produced by reacting maleic acid anhydride with mixtures of oleflnstm roduce a mixture of alkenyl succinic acid anh es. This mixture is then fractionated into severakcuts, thus producing products consisting of mixtureso alkenyl succinic acid anhydrides covering a relatively short carbon atom range. Three different products were used in the following examples, one of which was a mixture of alkenyl succinic acid anhydrides in which the alkenY r8-d cals averaged 6 to 8 carbon atoms in length, asecond was a similar mixture of anhydrides in which the alkenyl radicals averaged 8 to 10 carbon atoms in length, and the third, a similar mixture of anhydrides in which the alkenyl radicals ranged from 10 to 12 carbon atoms in length. The general structure for these compounds may be considered to be:

H o R-t-c where R is a mixture of alkenyl groups having an average of from 6 to 8, 8 to 10, or 10 to 12 carbon atoms. The mixtm'es used in the following examples were those manufactured and sold by the Solvay Process Company of New York, New York.

The primary amines used in the following examples were likewise of a commercial quality, rather than chemically pure, except where otherwise noted. These commercial-quality primary amines are 97% pure and contain predominantly the number of carbon atoms indicated. They are obtained by converting fatty acids, derived from natural fatty acid glycerides, into nitriles and then carefully reducing the nitriles to the primary amines, at temperatures below 150 C., and under alkaline conditions. The commercial amines used in the following examples are manufactured and sold by Armour & Company of Chicago, Illinois under the tradenames Armeen C Armeen SD," Armeen 8D," Armeen 10D," "Armeen 12D, "Armeen 14D, Armeen 16D," and Armeen 18D. Armeen CD" is a mixture of primary amines prepared from coconut oil, Armeen SD" is a mixture of primary amines prepared from soybean oil, and the other Armeens are mixtures of primary amines containing predominantly the number of carbon atoms specified in the code number. Theoretical neutralization numbers are based on the assumption that the amine can neutralize half of the available acidity in the anhydride.

EXAMPLE I A commerciai 010-12 alkenyl succinic acid anhydride of the type described above, and Armeen CD were reacted in a 2:1 molar ratio by placing in a beaker 14.5 g. of the anhydride and 5.0 g. of

Further details of this invention and further adthe amine. The reactants were stirred together, the heat of reaction raising the temperature to about C. The mixture was then placed in an oven at -110 C. for about 1 hour. The reaction product was a fairly viscous, amber colored liquid with a neutralization number (milligrams of KOH equivalent to 1- g. of products) of 191.

The theoretical neutralization number of this product was calculated to be 140.

EXAMPLE II A commercial Clo-l2 alkenyl succinic acid anhydride was reacted with "Armeen D" in a closed flask in the absence of air by placing 60 g. of the anhydride in a 4-necked, 200 cc. flask flushed with nitrogen gas, and heating the anhydride to 109 0., still in an atmosphere of nitrogen. 15.9 g. (0.1 g. excess for drainage) of Armeen 10D was then placed in a dropping funnel in which an atmosphere of nitrogen gas was maintained during the subsequent operation, and this amine was added dropwise to the anhydride at a rate sufiicient to raise the temperature in the flask to 113 C. and to maintain it at that temperature without the application of external heat. After the addition of the amine was completed, the flask was heated and stirred at 115 C. for 3 hours. The product was a dark, amber colored viscous liquid and there was no deposit on the walls of the flask. The neutralization number of the product was 161.9, whereas theoretically it should have been 152.9.

A number of other products were prepared by the above methods by using different amines and different anhydrides. In the tables which follow,

the manner of preparation will be designated by a numeral I or II, these numerals serving to designate that the product was prepared in accordance with Example I or in accordance with Example- Time, Hours The theoretical neutralization number for this product is 158. The indication therefore is that the reaction was substantially complete in a period of about 3V 'hours. The effectiveness of the various products prepared in accordance with this invention, as rust inhibitors, was determined in accordance with ASTM test D665-44T for determining Rust preventing characteristics of steam turbine oils in presence of water. In accordance with this test, both synthetic sea water and distilled water are used. The synthetic sea water contained 25 g. of sodium chloride, 11 g. of magnesium chloride (MgC1z.6HaO), 4 g.

of sodium sulphate and 1.2 g. of calcium chloride per liter. In the test a cylindrical. polished steel specimen is suspended and soaked in 300 cc. of the oil under test at 140 F. for 30 minutes. 30 cc. of synthetic sea water (or 30 cc. of distilled water) are added and the mixture is stirred at 1000 R. P. M. After 48 hours the steel specimen is removed and examined for evidence of rust. The oil passes the test when there is no evidence of rust on that part of the specimen which hangs below the oil level.

In the following tests, various of the reaction products of this invention were blended with a base oil commonly used for rust inhibiting tests. This oil was a blend of a solvent refined Mid- Continent residual stock with a solvent refined Mid-Continent (Rodessa) distillate stock which gives an oil having a specific gravity of 0.872, a flashpoint of 445 F. and a Saybolt Universal viscosity of 407.7 seconds at F. Such an oil is suitable for use in steam turbines.

To determine whether or not the addition of the reaction products of this invention to oils would cause the formation of undesirable emulsions, emulsion tests were also conducted on the oil-reaction product mixtures in accordance with the emulsion test for lubricating oils described-in the Federal Stock Catalog, sec. IV, part 5, Federal Specifications VV-L-791b, February 19, 1942. In accordance with test method 320.13, 40 cc. of oil and 40 cc. of a standard emulsant are placed in a 100 cc. cylinder and stirred with a paddle at 1500 R. P. M. for 5 minutes at the prescribed temperature. Separation of the emulsion is observed while the cylinder is kept at the prescribed temperature for the specified time. The figures in the tables show the number of minutes during which an emulsion layer persists between the oil and the emulsion. not to be emulsive if there is no continuous emulsion layer after 30 minutes. See Tables II, III and IV.

Similar tests were conducted on the alkenyl succinic acid anhydrides used in preparing the 5 reaction products and hydrolyzed alkenyl succinic An oil is usually considered Tests 11 Products of 2 moles C'ro-rz anhydride and 1 mole primary amine.

h A. s. 'r. M. Rust Test Ooncen Govt. Emulsion Method of Neutraliza tration Amine Used Preparation on 1 g Synthetic Seawater Distilled Water li regk aM irg Rwult Remarks Result Remarks Armeen on.--- I 191.0 6.10 Grey ma 0.06 ...do-.-.- do 17/10 17/10 0.02 Light gray coat.

0.01 ha... 10-15 spots 0.006 Pam... 'Light grey coa ArmeenCD I 191.4 0.05 Penn" Grey coat Armeen on 1 168.0 8'1? (1 G Pm o m cm n-butylsmine--. I 167.4 LIX! .--d0..... y

Heavy grey coat Tau: II-Contlnued- Product: of 2 moles C104: onhydride and 1 mole primary amine.

A. B. T. M. Bust 'leet Concen- Method oi N eutrollzatratlon Govt. Emulsion Amine Used Preparation tlon No. lnBlends. Synthetic Seawater Distilled Water Break 1(Mln.)

Per Cent H NaOl Result Remarks Result Remarks 0.05 12 13 n-octylamlne I 183. 3 0.05 15 18 Armeen 8D I 188. 2 0. 05 18 15 i 2 lar g e tch es.- Armeen D I 188. 8 0.05 Gray 10 16 do 11 101.9 0.05 n 14 10 0.02 n dn 0. 01 Fail-.--. Severe rust 0.000 Pass-. Perfect.-. 0.001 Fall.-.-. Severe rust I 175. 1 0. 05 Poem... Gray coat 15 16 I 195.3 0.05 do (In 15 17 1 169.0 0.05 .o.-... 15 17 I 157.1 2.0 n Heavy eoat.-.-

1.0 n rln 0.05 4.o..-.. Gray coat 17. 16 0.02 I 0 do I 175. 1 0. 05 n fin 14 15 I 191.3 0.05 do do 12 12 I 175. 5 0. 05 do.. Yellow coat 17 14 I 183.8 0.05 ---do..- Gray mat 10 14 Tun 111' Products of 2 moles of Ce-u anhydride and 1 mole primary amine A. 8. T. M. Rust Test Conmn- E Method at Neutrallw tretlon m Amine Used- Bynthetlc Seawater Distilled Water Break (Min.

Preparation tlon No. in Blends,

P01 ceul. H50 1% N8 1 Result Remarks Result Remarks I 215.5 0.05 Pass...'. Gray eoat 16 17 I 111:." 102.2 0.05 o dn (3% 150.4 0.05

n-butylamine..." I 218.5 0.2 Fall-.. Gum stalu..

- 0.05 d PHIL.-- Lt. coat... 10 11 Armeen 8D I 2%.6 1.0 0.05 12 10 Armeen 10D 216. 2 0. 05 12 12 Dn 211.5 0.05 Armeen 12D 1%. 5 0.05 12 16 Armeen 14D 195.3 0. 05 V 14 14 Armeen 15D.; 201.3 0.05 do 15 15 Armeen 18D-- 180. 9 1.0 Heavy brown 0. 05 Light mat 1e 15 0. m epntq 0.01 do Armeen 5D I 164. 9 0.05 Light coat 14 14 Cyclohexylamim- I 225.8 rowneoe 0105 Pass.... Lt. coat--- 1o 12 Benzylamino I an. 1 0. 2

0.05 Mod. rust Pam-.. Lt. coat--. 5 6 Aniline-.. I 210. 0 0. 2 Heavyacoat.

' 0.1 1 Fat 0.05 L ght rust Pass..;- Lt. coat... 8

Team IV Products of 2 motes Co-s anhydride and 1 mole primary amine A. 8. '1. M. Bust Test Ooncen- Govt Emulsion Method 01 Neutrallzatratlon Amlne Used Pmpamtmn on 1 g z Synthetic Seawater Distilled Water 7 liireakio lsMNl-lgl Result Remarks Result Remarks 1 221.8 0.05 Fall..- Severe... Fall. Mod. rust. 5 5

0.10 do Severe..-. I 199.3 0.05- Fe.l.--.. Mod. rust ---do'..... 200spots-. 4 5 1 was 0.05 n Bea rust 0 0 o 11 204.0 0.05 .-.d.o..... Lt.- 0d ass.... Perfect... I Armeen 18D. 11 189.3 0 Severe upper 35. gall... 3 spots.. 8 0

ass

accuses Tears V Alkenyl succinic acid anhydride A. S. T. M. Rust Test Neutmma Concentration a Material ti D No Blend, Synthetic Seawater Distilled Water Per Cent Result Remarks Result Remarks C 460. 0. 05 Severe.

0.02 Do. Hydrolyzed C 0. 438. 7 0. 05

0. 02 Gm coat. 010- 384- 2 0. 05 M 111st- 0. 02 Severe. Hydrolyzcd C t-1:--. M9. 9 0. 04

0.02 Perfect. 0. 01 Gray coat.

The results of the test in Table VI indicate that it is necessary to use temperatures in excess of 75 C. to produce the preferred type of products and that it is desirable to use a molar ratio of at least 1.25 to 1 of anhydride to amine in order to produce the preferred type of products. The

products prepared at 75 C. and the products prepared using a 1 to 1 molar ratio did show some rust inhibiting characteristics. However, the data obtained indicate that it is distinctly The results of these tests are shown in Table VI.

preferable to use a molar ratio of at least 1.25 to 1 and a temperature in excess of C. In order to obtain the most satisfactory type of product, it is far preferable to use a temperature of C. or above in the preparation of the reactio products.

Tests of oils containing other additives in addition to the reaction products of this invention have indicated that no incompatibility exists and that practically any other additive which it is desired to add may be added without affecting the beneficial results obtained by the addition of the reaction products of this invention and without impairing the effectiveness of the other additives.

TABLE VI Reaction products of 010-12 anhydrides and Armeen 10D in various molar proportions-Tested by A. S. T. M. rust test in synthetic seawater Tests conducted by a modification of the proposed ASTM method of testing the oxidation characteristics of steam turbine oils, according to which modification the oil is subjected to a tem-' perature of 203 F. (95 C.) in the presence of water, oxygen (3 liters per hour), and an ironcopper coil suspended in the oil above the water layer. for a period of 1000'hours, also indicated that the reaction products of this invention are highly efiective as rust preventatives.

The results of Brown-Boveri turbine oil tests have also been very satisfactory and show that the reaction products of this invention impart no sludging properties or other undesirable characteristics to the oil blends in which they are incorporated. I

Atmospheric corrosion tests further indicate that oil compositions including a minor percentage of the reaction products of this invention are highly effective in preventing atmospheric corrosion.

As used in the claims alkenyl succinic acid anhydride is intended to include a single anhydride, a mixture of anhydrides and the corresponding alkenyl succinic acids. Similarly, primary amine is intended to include a single amine and a mixture of amines.

What is claimed is:

1. A liquid hydrocarbon vehicle containing between about 0.03 per cent and about 10 per cent, by weight, of the reaction product obtained by reacting an alkenyl succinic acid anhydride with a primary amine, in a molar proportion of at Products Prepared at 0. Products Prepared at 75 0. Mi i M] r t i 0 es 0 0 es o in ion in Anhydride Amine Blend Per Neutmum A. S. T. M. Rust Test eutm w A. S. '1. M. Rust Test cent tion No. tion No.

Result Remarks Result Remarks 2 1 0. 05 161.9 Pass Heavy coat 212.4 Fail. 50 spots 0.03 do Light mat 0.02 0.01 l. 75 1 0.05 0. 04 0.03 0.02 1. 5 1 0. 05 0.04 0.03 0.02 l. 25 l 0. 05

0.03 0.02 7 large patches I 1 1 0.10 Med. rust 128. 7 Fail. Mod. rust.

.05 do do.... Mod. Heavy.

- least 1.25:1, respectively, and at a temperature varying between about 75 C. and about 140 C.,; the sum of twice the number of carbon atoms per molecule of said alkenyl succinic acid anhydride and of the number of carbon atoms per molecule of said primary amine being between 28 and 50. 2. The composition defined in claim 1, wherein said liquid vehicle is a mineral lubricating oil.

3. A mineral lubricating oil containing between about 0.03 per cent and about 10 per cent, by weight, of the reaction product obtained by reacting an alkenyl succinic acid anhydride with a primary, aliphatic amine, in a molar proportion of at least 1.25:1,respectively, and at a temperature varying between about 75 C. and about 140 C.; the sum of twice the number of carbon atoms per molecule of said alkenyl succinic acid anhydride and of the number of carbon atoms per molecule of said primary amine being between 28 and 50.

4. A mineral lubricating 011 containing between about 0.03 per cent and about 10 per cent, by weight, of the reaction product obtained by reacting an alkenyl succinic acid anhydride, having between about six and about eight carbon atoms per alkenyl radical, with dodecylamine, in a molar proportion of about 2:1, respectively, and a temperature varying between about 105 C. and about 115 C.

5. A mineral lubricating oil containing between about 0.03 per cent and about 10 per cent, by weight, of the reaction product obtained by reacting an alkenyl succinic acid anhydride, having between about eight and about ten carbon atoms per alkenyl radical, with aniline, in a molar pro-.

portion of about 2:1, respectively, and at a temperature varying between about 105 C. and about 115 C.

Y 0. A mineral lubricating 011 containing between about 0.03 per cent and about 10 per cent, by weight, of the reaction product obtained by reacting an alkenyl auccinic acid anhydride having between about ten and about twelve carbon atoms per alkenyl radical, with a primary, aliphatic amine, having between about ten and about fourteen carbon atoms per molecule, in a molar proportion or about 2:1, respectively, and at a temfigatgre varying between about 105C. and about '1. A mineral lubricating 011 containing between about 0.03 per cent and about 10 per cent, by weight, of the reaction product obtained by reacting an alkenyl succinic acid anhydride, having between about ten and about twelve carbon atoms per alkenyl radical, with a primary, aliphatic'amine prepared from coconut oil, in a molar proportion of about 2:1, respectively, and at a temperature varying between about 105 C. and about 115 C.

HASTINGS S. TRIGG. HENRY D. NORRIS. RALPH v. WHITE.

REFERENCES CITED The following references are of record in the filevoi this patent:

UNITED STATES PATENTS 

